While there are many reasons for a car to idle roughly, one of the most common is a vacuum leak. Even small leaks can cause the rough idle and illuminate the check engine light. Unfortunately the problem is often difficult to find, but once it's located, it's easy to fix. Popular Mechanics recommends starting with a copy of the vehicle's vacuum diagram and highlighting each connection when checked.
The government requires automobiles have an EGR valve that increases efficiency and a more complete burn of fuel. It recirculates a portion of the vehicle's exhaust through the combustion chamber to cool the temperature at which the fuel burns and decreases noxious emissions. The EGR system decreases the vehicle's contribution to the build-up of greenhouse gases. When this valve goes bad, it affects the engine idle. In addition to its effect on the engine performance, a bad EGR valve has the potential to stop the engine from running altogether. About.com recommends owners try to clean an EGR valve with carburetor cleaner before replacing it. It suggests cleaning valves without an electrical connection by soaking in cleaner overnight if possible. If the valve has a connection, it requires the use of a spray cleaner and brushes after removal from the vehicle.Learn More
A grating noise when accelerating a car is often a sign of bad brakes. The disk brake pads rest against the rotors at all times. When the material on the pad wears through, the metal plate that backs the pad rests against the rotor and makes the noise.Full Answer >
When a car sputters as it idles, this means the car is either not getting enough power or fuel. To test the problem, the driver presses down on the gas peddle. If doing so makes the car stop sputtering, there is a problem with fuel delivery. If this does not help, there is a problem with the power supply.Full Answer >
A "low coolant" warning on a vehicle usually means that the vehicle is low on the cooling fluid inside the systems that prevent overheating of the engine. The coolant level can be verified by checking the coolant backup tank under the hood once the engine is cool.Full Answer >
The check gauges light illuminating in a vehicle simply indicates that one or more gauges is giving an abnormal reading. For example, the car could be running hot, or the gas could be low. In this case, the respective gauge light should also be lit. As soon as the problem indicated by the gauge is fixed, the light generally goes off.Full Answer >